Many businesses and governmental agencies process a large number of printed forms which, when completed, contain handwritten entries.
There are a number of known ways to extract and process the information contained in the handwritten entries on the forms and to store the information and the forms. For example, the data may be extracted using known image scanning devices and optical character recognition technologies to extract either the printed or handwritten data on the form. An image of the form itself may be stored, for example, by photographing the document onto microfilm or microfiche, or by optically scanning the form and storing an electronic image of it on laser disk or other electronic storage medium. Image scanning devices and optical character recognition ("OCR") technology are well known and commercially available. An OCR device improved over these known devices is disclosed in related application Ser. No. 08/489,945.
FIG. 1 is a block diagram of a typical OCR system 50, such as may be used with the present invention. This system 50 includes a paper transport system 51. The paper transport system 51 moves the forms in the direction of the arrow past an optical scanner ("OCR scanner") 52. A preferred embodiment of the OCR scanner 52 forms a digital image of a form by illuminating the form with a bright light such as a laser light and then recording the reflected light using storage devices such as CCDs. This type of scanner may be used to form a bitonal digital image wherein each pixel is either white or black, corresponding to logic "1" or logic "0". One such OCR scanner 52 is a model TDC2610W, manufactured by Terminal Data Corp.
The scanner 52 may be connected to a processor 54, such as a general purpose computer or a special purpose hardware processing element. The processor's hardware elements may be optical processing elements or electronic processing elements such as resistor summing networks and digital logic circuits. The processor may include a microprocessor 56 and other components; a screen or monitor 58; and a keyboard or other input device 60. The processor 54 may also include a memory device 62 for storing the scanned documents. This memory device may be, for example, a disk memory, a RAM, or other memory device.
The forms to be read are scanned in the OCR scanner 52. Information on the forms may be provided in fields (i.e., a "name" field, an "address" field, etc.). Before the forms are scanned, the processor 54 may already have "learned" the location and expected content of particular fields. For example, the processor 54 may have "learned" that a handwritten address is expected at a particular location on a particular document (see, for example, U.S. patent application Ser. No. 08/489,945). The image data information is processed in the processor 54. During processing, an image of the scanned forms and character recognition information may be displayed on the screen 58.
Character recognition systems, particularly those which recognize handwritten characters, cannot guarantee a completely error free recognition. Recognition mistakes inevitably occur. Thus, some manual editing (i.e., performed by a human editor) is typically needed. In some conventional systems, character recognition systems often refuse to recognize characters that are sloppily written or illegible, so that the ratio of correctly to incorrectly recognized characters increases. This higher recognition correctness rate makes an automated system more valuable than a manual data entry system, wherein a human data processor reads a document and manually types the data. Therefore, it is a desirable characteristic of an optical character recognition system to provide an efficient method for manually editing unrecognized or rejected characters, words, or field entries.
Optically recognized documents may be classified into one of the following three categories:
1. "Correct" or Full Automatic Recognition: each character on the document is recognized and the document as a whole passes all integrity checks such as dictionary (i.e., recognized characters form a known word) and grammar (i.e., recognized words form grammatically correct phrases or sentences) processing. No additional editing is required and any recognition mistakes in the document are due to system inherent errors. For a practical system, the inherent error rate of the system should be lower than that of a manual entry system. PA1 2. Manual Editing Required: a document requiring some manual editing. If a number of characters on the document are rejected (i.e., the character cannot be recognized) or whose recognition results do not pass integrity checks (i.e., the recognized characters do not form a recognized word or recognized words do not form a valid phrase or sentence), the document is manually edited. PA1 3. Rejected Document: a document rejected by the recognition system. A rejection could be caused, for example, by a poor quality scanned image, form error, or sloppy handwriting. The data on a rejected document must be entirely manually processed.
OCR devices typically include a screen editing fiction which displays rejected documents on a computer screen and allows an editor to input corrections. Generally, an image of the entire form, or a large portion (or "block") of the entire form, containing a rejected character is displayed on the screen so that the data entry operator need not refer to the original (hard copy) document. This method is satisfactory for processing a relatively small number of documents. Where a large number of documents--i.e., millions of strokes (characters) requiring dozens of data entry operators--this method is not efficient because each rejected document is displayed on the screen, regardless of the number of rejected characters in the document. Thus, even if a single character is rejected in a document, the entire document appears on the screen. This results in a bottleneck that slows down the entire OCR process.
Optical character recognition systems have addressed some of these problems. For example, U.S. Pat. No. 5,251,273 to Betts et al. discloses a data processing system and method for sequentially correcting character recognition errors for scanned images of document forms. The device disclosed in this reference has three recognition coded data correction processors. These correction processors are (1) an artificial intelligence processor, (2) a database error processor, and (3) a manual verification and correction processor. A machine-generated data structure records recognition results and correction histories and transfers these to each consecutive processor. After the artificial intelligence and database error correction processes are complete, field data segments may be displayed on a workstation for manual correction.
U.S. Pat. No. 5,305,396 to Betts et al. discloses a data processing system and method for selecting customized character recognition processes and coded data correction processes for scanned images of document forms. This reference discloses entering a document form processing template. The template includes customized system operation parameters which the data processing system reads before a completed form may be recognized.
U.S. Pat. No. 5,235,654 to Anderson et al. is directed to an advanced data capture architecture data processing system and method for scanned images of document forms. This reference discloses a system for generating new document forms for automatic processing.
U.S. Pat. No. 5,153,927 to Yamanari discloses a character reading system and method which allows a user to prepare a user specific processing program without knowing all of the specifications of the processing program. This reference discloses two processing sections, a standard processing section and a user defined processing section. The user-defined processing section allows the user to arbitrarily set a field which the user wants to check without affecting the standard processing section.
U.S. Pat. No. 5,233,627 to Yamanari et al. is directed to a character reader and recognizer with a specialized editing function. This reference discloses a character reader device which avoids a situation where the image data displayed on a workstation screen overlaps an area for displaying a particular image containing a rejected character.
U.S. Pat. No. 5,123,062 to Sangu discloses a screen display layout of an entire scanned document image and displays the recognition results obtained during the recognition process.
It is an object of the present invention to provide an efficient method of performing OCR screen editing.
It is another object of the present invention to provide an OCR screen editing method that has an easily understood screen layout.
It is yet a further object of the present invention to provide a screen editing method where only portions of a form may be displayed for editing.
It is yet an even further object of the present invention to provide a method for simultaneously screen editing a number of scanned documents.